Displays are widely applied due to numerous advantages such as thin bodies, energy saving, radiation-free, etc. Most displays available on the market are backlight-type displays, and such a display includes a display device and a backlight module. The working principle of the display device is placing liquid crystal molecules between two parallel substrates, and applying a driving voltage on the two substrates to control rotation directions of the liquid crystal molecules, for refracting rays from the backlight module to generate images.
A thin film transistor-liquid crystal display (TFT-LCD) gradually occupies the dominant position in the display realm at present because of its properties such as low energy consumption, superior image quality and relatively high production yield, etc. Identically, the TFT-LCD includes a display device and a backlight module. The display device includes a color filter (CF) substrate and a thin film transistor (TFT) substrate. The opposite internal sides of the substrates have transparent electrodes. A layer of liquid crystal (LC) molecules are interposed between the two substrates. The display device alters the polarization state of light under the control of the electric field on the orientation of liquid crystal molecules, and achieves the objective of display via blocking or unblocking the optical path through a polarizer.
As the usage of displays is prevalent, users spend more time on the displays, including a mobile phone, a monitor, a laptop, a pad, a TV, even some smart watches, and all of the displays employ a LCD (Liquid crystal display) or an OLED (Organic light emitting diode) as the display element. However, some medical journals and professionals have alarmed the danger of blue light emitted from the display. Eyes would be chronically hurt during the long term irradiation of blue light with short wavelengths from the display, or resulting in blindness in some severe situations. LCDs equipped with blue LED chips as the backlight or OLED blue display elements are necessary to be designed to prevent the harm of blue light on eyes.